Large pied cormorant description

As its name suggests, the large pied cormorant (Phalacrocorax varius) is a relatively big cormorant species with conspicuous black and white plumage (3)(4).

During the breeding season, the black feathers on the forehead, crown and nape of the large pied cormorant contrast sharply with the white of the face and neck (3). Non-breeding adults are duller and more brownish in colour (2)(3). All of the bird’s undersurface is pure white (4), while the short legs and large webbed feet are black (3)(4).

The large pied cormorant has short, broad wings, a short tail, and a long neck (3). Its pale, sea-green eyes are accentuated by a bare patch of rich indigo-blue skin below each eye, and a patch of bright orange skin in front (4). The long, stout, horn-coloured bill of this species becomes lighter towards the tip, and ends in a prominent hook (3)(4).

Both sexes of the large pied cormorant are alike in terms of plumage colouration (4), but the female is generally smaller and has a shorter bill than the male (2). In place of the black feathers, juvenile large pied cormorants have dark brown plumage, and their underparts are streaked or mottled brownish grey (2)(4).

Two subspecies of the large pied cormorant are often recognised. These races are separated on the basis of slight differences in colouration, with Phalacrocorax varius hypoleucos having a blue sheen to its black feathers, as opposed to the green sheen found in Phalacrocorax varius varius(2).

Related species

Large pied cormorant biology

An agile aquatic hunter, the large pied cormorant feeds mostly on fish (2)(3)(4)(5), which it catches by pursuing them underwater (2). Impressively, these dives last an average of 26.5 seconds (8). While approximately 90 percent of its diet comprises a wide variety of fish species (2)(5), the large pied cormorant also feeds on crustaceans, such as shrimps and crabs, as well as some molluscs, including cephalopods(2)(5). Several introduced fish species, including carp (Carassius auratus) and perch (Perca fluviatilis), are an important component of the large pied cormorant’s diet, particularly in the estuaries of southwestern Australia (2).

The large pied cormorant is known to form feeding flocks at sea (2)(5), and can be seen resting on sandbanks or low rock edges after fishing (4). The large pied cormorant roosts and breeds colonially, with roosting generally occurring in trees near water and in association with other cormorant species, spoonbills and Australian pelicans (Pelecanus conspicillatus) (2)(3). The breeding season of the large pied cormorant varies considerably with geographical location, as well as between years, with local water conditions and resource availability being important factors in its onset (2)(3)(5). However, although breeding may occur at any time of the year, the main breeding season appears to be between spring and autumn (2)(3).

The large pied cormorant tends to nest in trees, bushes or sometimes on the ground (2)(4), on islands or in swamps (2) at sites where the water levels are relatively stable, such as along the coast (3). However, this species is also known to breed at inland locations, although this tends to occur opportunistically in response to extended flooding conditions (3). Large pied cormorant nests are formed of twigs, seaweed (2)(3) and occasionally rubbish (3), and are sometimes lined with grass (2).

The large pied cormorant typically produces a clutch of between 1 and 5 eggs, although 3 is most common (2), with the eggs being laid at intervals of 48 hours (3). Large pied cormorant eggs are pale bluish-white (4), and are incubated for between 25 and 33 days (2)(3). Once the chicks reach 34 days of age, they are able to walk from the nest, but return to it for the next 4 weeks (3). The chicks are able to fly at about 47 to 60 days old, although the young are not fully independent from the adults until they are 80 days old or more (2)(3). While some large pied cormorants are capable of breeding at one year of age, most do not reach sexual maturity until they are two years old or more (2).

The large pied cormorant is a non-migratory species, with adults usually remaining in the same location. However, juveniles tend to disperse from the breeding grounds in which they hatched (2)(5).

Large pied cormorant range

The large pied cormorant only occurs in Australia and New Zealand (5)(6)(7), including Stewart Island (7).

This species is widely distributed in Australia (2)(5), wintering across Queensland, New South Wales and Victoria, and along the coastlines of other states (3)(5). It has even been recorded as a vagrant in Tasmania and on Lord Howe Island off the east coast of Australia. However, the large pied cormorant is known to be absent from Australia’s arid interior (2). Breeding occurs on New Zealand’s North Island, with some scattered coastal breeding sites in Australia (5).

The large pied cormorant is sometimes split into two subspecies, with Phalacrocorax varius hypoleucos being found in Australia, and Phalacrocorax varius varius being found in New Zealand (2).

Species with a similar range

Large pied cormorant habitat

Generally considered to be a predominantly marine species (2)(3)(5)(6), particularly in Western Australia (2)(5), the large pied cormorant can often be found occupying a variety of sheltered coastal waters, including mangroves, estuaries and bays (2)(5)(7). This species is known to be particularly gregarious in such areas, especially where the shores are sandy and flat, and where there is an abundant supply of fish (4). It can also be found on offshore islands (2)(5).

Although coastal areas appear to be the large pied cormorant’s preferred habitat, this species can also be found inland (2)(3)(5), inhabiting large wetlands such as lakes, swamps, reservoirs and rivers (2)(3). These areas tend to be large, permanent bodies of open water (2)(3), with the large pied cormorant being less common in shallow vegetated waters and semi-permanent swamps (3).

Large pied cormorant status

Large pied cormorant threats

A widespread species in Australia (2)(5), the large pied cormorant is not currently considered to be globally threatened (2), particularly as its preferred habitats are less affected by transformation and destruction than those of several other species (2).

However, the large pied cormorant feeds extensively on a variety of introduced fish species, and it is thought that campaigns to rid the region of the fish could have a negative impact on this water bird (2).

Large pied cormorant conservation

There are currently no known conservation measures in place specifically for the large pied cormorant. However, it is thought that this species has benefitted from an increase in the number of artificial water bodies within its range, and it is also known to use man-made structures to perch and breed on (2).

Authentication

Glossary

A group of marine molluscs with grasping tentacles and either an internal or external shell. Includes squids, octopuses, cuttlefish and nautiloids.

Colonial

Relating to or belonging to a colony (a group of organisms living together in a group).

Crustaceans

Diverse group of animals with jointed limbs and a hard external skeleton, characterised by the possession of two pairs of antennae, one pair of mandibles (mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps, woodlice and barnacles.

Incubate

To keep eggs warm so that development is possible.

Molluscs

A diverse group of invertebrates, mainly marine, that have one or all of the following: a horny, toothed ribbon in the mouth (the radula), a shell covering the upper surface of the body, and a mantle or mantle cavity with a type of gill. Includes snails, slugs, shellfish, octopuses and squid.

Nape

The back of the neck.

Subspecies

A population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.

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